The .50 BMG, .308, And The .223

[Badgersmilk]

Most EVERYTHING you may ever want to know about military small arms ammo.  Including land mines, RPG's, and most anything else.  Neat stuff to read.  Still looking for why they'd want to have all their brass annealed though.  I know all about handloaders doing it to prevent work hardening of the brass, leading to neck cracks.  Just wondering what the military perogitive was.

http://www.scribd.com/doc/12887234/Ammunition-General

[billt]

Just wondering what the military perogitive was.

Better gas seal at the case neck. Especially with machine gun rounds. M-2's fired a bit cleaner with less blow by.  Bill T.

[Badgersmilk]

After nearly going blind reading manuals, I've found bit's of answers in a few of them.  This one sums it up as well as any.  http://www.scribd.com/doc/4934783/BALLISTICS-AND-AMMUNITION

Military brass cases use 70% one material 30% another (I'm not going back in there to see what they were. brass & copper I believe), ALONG WITH the steel, and aluminum cases used (as well as "other metals") they're all hardened to the point that if the necks of the cases were not annealed, they wouldn't flex enough to seal in gases upon firing.  SO, military brass is harder than commercial brass, thus, HAS to be annealed at the neck to prevent blow back gases, and case splitting even on the first firing.  

I need a beer now!  

[Badgersmilk]

Oh, I also learned.  Among other things, the military case walls and heads need to be harder than commercial stuff due to possible use in belt fed weapons (I've had Remington commercial .308 brass I could squish nearly flat with my fingers it was so soft.).

I was just curious.  

[Big Frank]

I had some mil-spec ammo that looked like it wasn't annealed. I guess they polished the color off.

[Sponsor]

[philw]

I HATE you



love the picks  would love to here a range report ( must have picks though )

[billt]

Brass itself is a "funny" kind of metal. By that I mean it is difficult to achieve consistent hardness from heat to heat. That, combined with the amount of draw steps can result in very hard cartridge brass that, without annealing, can fail on the first firing. The fact the .50 BMG case is thick and long makes this condition worse as far as sealing the chamber at the case neck. That is the main reason you rarely see .50 BMG cases that are not annealed. Some may appear to be, but that is from vigorous tumbling and polishing.

The most consistent, workable brass comes from Lapua. It goes through several heat treatment processes that prevents the metal from over hardening and becoming brittle through the entire drawing process. They are also annealed. They also eliminate stress in the case by drilling the flash hole instead of punching it. It is not at all uncommon for benchrest shooters to reload a single Lapua case 2 dozen times or more. I purchased 200, .308 Lapua cases, and you can tell the difference by how easily they go through a resizing die. Very smooth and effortless, and they require less lubrication as well. I'm told Nosler brass is of very high quality, but as of yet I have not tried it.  Bill T.

[kilopaparomeo]

As long as we're posting size comparisons, here's a .50 BMG, 6.5 Grendel and 5.56 all based on the AR platform

[philw]

As long as we're posting size comparisons, here's a .50 BMG, 6.5 Grendel and 5.56 all based on the AR platform

just added you to my I HATE YOU list      

[billt]

As long as we're posting size comparisons, here's a .50 BMG, 6.5 Grendel and 5.56 all based on the AR platform

How does that big cartridge get through that little bitty mag well??      Bill T.